Step 1:
I taped a black paper to a yellow paper.
You can also print or draw a black square on a yellow paper.
Prefold over these 2 lines.

Step 8:
Fold over the 2 pink lines first, then over the blue lines.

Step 6:
Prefold the edges to the spots indicated by the arrows.

Step 13:
Fold over these 2 lines

Step 12:
Fold over these 3 lines

Step 11:
Here a part of step 10 is already done, press both corners inwards, see arrows. Then press the whole model flat again.

Step 10:
Fold the edges backwards

Step 9:
Fold the corners to the spots indicated by the arrows. Use the white prefolded lines as guidance.

Step 5:
Fold the edge to the spot indicated by the arrow.

Step 7:
Pull open

Step 3:
Prefold over the left line and fold over the line on the right (fold the corners to the prefolded lines).

Step 2:
Prefold the corners to the center.

Step 4:
Fold over these 2 lines

Step 14:
And fold over these 2 lines.

Done! This really makes me happy and lolz :-)

And this is an Origami DIY video for folding the Smiley face: